Eye Position Stability in Amblyopia and in Normal Binocular Vision

2012 ◽  
Vol 53 (9) ◽  
pp. 5386 ◽  
Author(s):  
Esther G. González ◽  
Agnes M. F. Wong ◽  
Ewa Niechwiej-Szwedo ◽  
Luminita Tarita-Nistor ◽  
Martin J. Steinbach
Keyword(s):  
Binocular Vision ◽  
Eye Position ◽  
Normal Binocular Vision

scholarly journals Effect of corneal refractive surgery on accommodative and binocular dysfunctions among civilian pilots in Southwest China

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Ye Wu ◽  
Zhen Zhang ◽  
Meng Liao ◽  
Qi Li ◽  
Xue Lin Tang ◽  
...  
Keyword(s):  
Binocular Vision ◽  
Refractive Surgery ◽  
Visual Symptom ◽  
Chi Square ◽  
Visual Symptoms ◽  
Significant Difference ◽  
Symptom Scores ◽  
Chi Square Test ◽  
Corneal Refractive Surgery ◽  
Normal Binocular Vision

Abstract Background To analyze whether corneal refractive surgery (CRS) is associated with the distribution of different accommodative dysfunctions (ADs) and binocular dysfunctions (BDs) in civilian pilots. A further aim was to analyze the percentages and visual symptoms associated with ADs and/or BDs in this population. Methods One hundred and eight civilian pilots who underwent CRS from January 2001 to July 2012 (age: 30.33 ± 4.60 years) were enrolled, the mean preoperative SE was − 1.51 ± 1.15 D (range: − 1.00- − 5.00 D). Ninety-nine emmetropic civilian pilots (age: 29.64 ± 3.77 years) who were age- and sex-matched to the CRS group were also enrolled. Refractive status, accommodative and binocular tests of each subject were performed. Visually related symptoms were quantified using the 19-item College of Optometrists in Vision Development Quality of Life (COVD-QOL) questionnaire. The 19 items were summed to obtain visual symptom scores that might indicate visual dysfunctions. The chi-square test was used to analyze differences in percentages of ADs and/or BDs between the CRS and emmetropic groups. The Mann-Whitney U test was used to compare visual symptom scores between pilots with ADs and/or BDs and pilots with normal binocular vision. Results No significant difference was observed between the CRS and emmetropic groups in the overall prevalence of ADs and BDs (15.7% and 15.2% in the CRS and emmetropic groups, respectively; P = 0.185). ADs were present in 4.63% and 3.03% of the CRS and emmetropic group, respectively. BDs were observed in 11.1% and 12.1% of the CRS and emmetropic group, respectively, yielding no significant differences between the groups in the prevalence of ADs or BDs (AD: P = 0.094; BD: P = 0.105). Pilots with ADs and/or BDs had significantly more visual symptoms than pilots with normal binocular vision (p < 0.001). Conclusions CRS for civilian pilots with low-moderate myopia might not impact binocular functions. ADs and/or BDs commonly occur in both emmetropia pilots and pilots who undergo CRS, and pilots with ADs and/or BDs are associated with increased symptoms. This study confirms the importance of a full assessment of binocular visual functions in detecting and remedying these dysfunctions in this specific population.

Recovery from effects of brief monocular deprivation in the kitten

1984 ◽  
Vol 51 (3) ◽  
pp. 538-551 ◽  
Author(s):  
R. Malach ◽  
R. Ebert ◽  
R. C. Van Sluyters
Keyword(s):  
Binocular Vision ◽  
Cortical Neurons ◽  
Striate Cortex ◽  
Ocular Dominance ◽  
Recovery Process ◽  
Complete Recovery ◽  
Monocular Deprivation ◽  
Cortical Input ◽  
Binocular Function ◽  
Normal Binocular Vision

The potential for recovery from the cortical effects of monocular deprivation (MD) was studied in kittens that were briefly deprived and then exposed to various periods of normal binocular vision. In eight kittens, recordings from the hemisphere ipsilateral to the deprived eye revealed that at 4 wk of age, exposure to 12 h of MD (six 2-h sessions spread over 2 days) was sufficient to cause a massive shift in the ocular dominance of striate cortex neurons in favor of the nondeprived eye. Six of these MD kittens were allowed 3 wk of normal binocular vision and then recorded from a second time to assess the extent to which their cortex could recover from the effects of this brief period of deprivation. Data from these animals indicated that now approximately equal numbers of cortical neurons were dominated by each eye and that, while the overall level of binocularity was somewhat lower than that found in normally reared animals, the majority of cells had regained functional binocular connections. The possibility that cortical binocularity could recover even further was explored by allowing four of these six MD kittens to experience an additional 4 wk of binocular vision and then recording from them a third time. These final recordings indicated that following a total of 7 wk of binocular vision, the level of cortical binocularity was no different from that found in normally reared animals. Having demonstrated that normal binocular function can be restored to a cortex in which it had been severely disrupted, we next attempted to characterize the earliest stages of this recovery process by examining the pattern of cortical binocularity in 10 MD kittens that were allowed to experience either 6 or 12 h of binocular vision (given over 1 or 2 days, respectively). Our results indicate that, during the initial day of binocular vision, recovery seems to involve a noncompetitive expansion of functional cortical input from the deprived eye, which joins with input from the nondeprived eye in driving cortical neurons. The level of cortical binocularity continues to increase during the next day of binocular vision, but now there is also a small increase in the proportion of cells driven exclusively by the initially deprived eye--suggesting that there may be an additional competitive component to the early stages of recovery. The results of this study complement our previous report of complete recovery of binocularity following exposure to a brief period of optically induced strabismus.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Hoya Eyegenius®: New Method for Measuring and Correcting Fixation Disparity

2017 ◽  
Vol 71 (5) ◽  
pp. 392-396
Author(s):  
Volkhard Schroth ◽  
Olga Prenat ◽  
Natalia Vlasak ◽  
Roger Crelier
Keyword(s):  
Binocular Vision ◽  
Direct Conversion ◽  
New Method ◽  
Digital Environment ◽  
Fixation Disparity ◽  
Blurred Vision ◽  
Digital Devices ◽  
Innovative Method ◽  
Normal Binocular Vision

Abstract Many things interfere with good binocular vision in nowadays modern digital environment: long periods spent looking at screens and switching between different digital devices at short distances. Vision-related or asthenopic complaints such as headaches, tired and burning eyes or blurred vision can be experienced by many people. Prescribing prismatic correction for fixation disparity can help to reduce these symptoms. A new, highly innovative method for measuring and correcting fixation disparity has been developed - HOYA EyeGenius®. The HOYA EyeGenius® method includes the unique examination procedures, pre-tests and fixation disparity measurements at far and near distances. The pre-tests allow to include patients with asthenopic complaints only with normal binocular vision and exclude cases with abnormal binocular vision. The main innovation of EyeGenius is based on direct conversion of the fixation disparity value into a prism amount. Therefore, the trial prismatic lenses are not used during the test. The use of digital devices makes this method interactive and minimizes the influence of the examiner.

scholarly journals The role of binocular vision in walking

2009 ◽  
Vol 26 (1) ◽  
pp. 73-80 ◽  
Author(s):  
MARY HAYHOE ◽  
BARBARA GILLAM ◽  
KELLY CHAJKA ◽  
ELIA VECELLIO
Keyword(s):  
Binocular Vision ◽  
Monocular Vision ◽  
Stereoscopic Vision ◽  
Eye Position ◽  
Visually Guided ◽  
Extensive Investigation ◽  
Foot Placement ◽  
Walking Performance ◽  
The Difference

AbstractDespite the extensive investigation of binocular and stereoscopic vision, relatively little is known about its importance in natural visually guided behavior. In this paper, we explored the role of binocular vision when walking over and around obstacles. We monitored eye position during the task as an indicator of the difference between monocular and binocular performances. We found that binocular vision clearly facilitates walking performance. Walkers were slowed by about 10% in monocular vision and raised their foot higher when stepping over obstacles. Although the location and sequence of the fixations did not change in monocular vision, the timing of the fixations relative to the actions was different. Subjects spent proportionately more time fixating the obstacles and fixated longer while guiding foot placement near an obstacle. The data are consistent with greater uncertainty in monocular vision, leading to a greater reliance on feedback in the control of the movements.

scholarly journals Effect of corneal refractive surgery on accommodative and binocular dysfunctions among civilian pilots in Southwest China

2020 ◽  
Author(s):  
Ye Wu ◽  
Zhen Zhang ◽  
Meng Liao ◽  
Qi Li ◽  
XueLin Tang ◽  
...  
Keyword(s):  
Binocular Vision ◽  
Refractive Surgery ◽  
Visual Symptom ◽  
Chi Square ◽  
Visual Symptoms ◽  
Vision Development ◽  
Significant Difference ◽  
Symptom Scores ◽  
Corneal Refractive Surgery ◽  
Normal Binocular Vision

Abstract Background: To analyze whether corneal refractive surgery (CRS) is associated with the distribution of different accommodative dysfunctions (ADs) and binocular dysfunctions (BDs) in civilian pilots. A further aim was to analyze the percentages and visual symptoms associated with ADs and/or BDs in this population.Methods: One hundred and eight civilian pilots who underwent CRS from January 2001 to July 2012 (age: 30.33±4.60 years) were enrolled, the mean preoperative SE was −1.51±1.15 D (range: −1.00- −5.00 D). Ninety-nine emmetropic civilian pilots (age: 29.64±3.77 years) who were age- and sex-matched to the CRS group were also enrolled. Refractive status, accommodative and binocular tests of each subject were performed. Visually related symptoms were quantified using the 19-item College of Optometrists in Vision Development Quality of Life (COVD-QOL) questionnaire. The 19 items were summed to obtain visual symptom scores that might indicate visual dysfunctions. The chi-square test was used to analyze differences in percentages of ADs and/or BDs between the CRS and emmetropic groups. The Mann-Whitney U test was used to compare visual symptom scores between pilots with ADs and/or BDs and pilots with normal binocular vision.Results: No significant difference was observed between the CRS and emmetropic groups in the overall prevalence of ADs and BDs (15.7% and 15.2% in the CRS and emmetropic groups, respectively; P=0.185). ADs were present in 4.63% and 3.03% of the CRS and emmetropic group, respectively. BDs were observed in 11.1% and 12.1% of the CRS and emmetropic group, respectively, yielding no significant differences between the groups in the prevalence of ADs or BDs (AD: P=0.094; BD: P=0.105). Pilots with ADs and/or BDs had significantly more visual symptoms than pilots with normal binocular vision (p < 0.001). Conclusions: CRS for civilian pilots with low-moderate myopia might not impact binocular functions. ADs and/or BDs commonly occur in both emmetropia pilots and pilots who undergo CRS, and pilots with ADs and/or BDs are associated with increased symptoms. This study confirms the importance of a full assessment of binocular visual functions in detecting and remedying these dysfunctions in this specific population.

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